Method for controlling a turbine engine comprising an electric machine

Abstract

The invention relates to a method for controlling a turbine engine (T) comprising an electric machine, the control method comprising a first fuel control loop (B1) determining a fuel flow rate setpoint (WFcmd) and a second torque control loop (B2) determining an electrical torque setpoint (TRQcmd), the torque control loop (B2) being configured to determine the electrical torque setpoint (TRQcmd) on the basis of a determined transient torque setpoint (TRQtrans), an earlier electrical torque setpoint (TRQcmd-1) and a transient phase indicator (TopTrans), the control setpoint (TRQcont) being determined on the basis of an earlier control setpoint (TRQcont-1), a time constant (tau) and the earlier electrical torque setpoint (TRQcmd-1) according to a decreasing mathematical law of the first order.

Description

Method for controlling a turbomachine comprising an electric machine

[0001] The present invention relates to a turbomachine for an aircraft, in particular, to the control of a turbomachine in order to provide the desired thrust as a function of the position of the control lever of the pilot of the aircraft.

[0002] Climate change is a major concern for many legislative and regulatory bodies around the world. Indeed, various carbon emission restrictions have been, are being, or will be adopted by various states. In particular, an ambitious standard applies to both new aircraft types and those already in operation, requiring the implementation of technological solutions to ensure their compliance with current regulations. Civil aviation has been mobilizing for several years now to contribute to the fight against climate change.

[0003] Technological research efforts have already led to very significant improvements in the environmental performance of aircraft. The Applicant takes into consideration the impact factors in all phases of design and development to obtain less energy-intensive, more environmentally friendly aeronautical components and products whose integration and use in civil aviation have moderate environmental consequences with the aim of improving the energy efficiency of aircraft.

[0004] Consequently, the Applicant is constantly working to reduce its negative climate impact by using methods and operating virtuous development and manufacturing processes and minimizing greenhouse gas emissions to the minimum possible in order to reduce the environmental footprint of its activity.

[0005] This sustained research and development work focuses on new generations of aircraft engines, the weight reduction of aircraft, particularly through the materials used and lighter on-board equipment, the development of the use of electrical technologies to ensure propulsion, and, as an essential complement to technological progress, aeronautical biofuels.

[0006] With reference to the, there is shown schematically a turbomachine 100 of the double-flow and double-spool turbojet type for aircraft. In a known manner, the turbomachine 100 comprises, from upstream to downstream in the direction of gas flow, a fan 110, a low-pressure compressor 111, a high-pressure compressor 112, a combustion chamber 113 which receives a fuel flow setpoint WFcmd, a high-pressure turbine 114, a low-pressure turbine 115 and a primary exhaust nozzle 116. The low-pressure (or LP) compressor 111 and the low-pressure turbine 115 are connected by a low-pressure shaft 121 and together form a low-pressure body. The high-pressure (or HP) compressor 112 and the high-pressure turbine 114 are connected by a high-pressure shaft 122 and together form a high-pressure body. The blower 110, which is driven by the low pressure shaft 121, compresses the ingested air.This air is divided downstream of the fan 110 between a secondary air flow which is directed directly towards a secondary nozzle (not shown) through which it is ejected, and a so-called primary flow which enters the gas generator, constituted by the low pressure body and the high pressure body, then which is ejected into the primary nozzle 116. In a known manner, to modify the speed of the turbomachine 100, the pilot of the aircraft modifies the position of a control lever which makes it possible to modify the fuel flow setpoint WFcmd in the combustion chamber 113.

[0007] The design of a turbomachine 100 requires taking into account a sufficient margin against the so-called surge phenomenon. This phenomenon, which results from an excessive incidence of the air flow on the blades of one of the compressors, results in significant and rapid fluctuations in the pressure downstream of the compressor concerned and can lead to extinction of the combustion chamber 113. It also generates significant jolts on the blades of the compressor and can thus lead to mechanical damage. It is therefore particularly important to avoid its occurrence. The operation of a compressor in use is generally represented by a diagram which expresses the pressure ratio obtained between the outlet and the inlet, as a function of the air flow passing through it; this diagram is further parameterized as a function of the rotation speed of the compressor.This diagram shows a surge line which constitutes the maximum limit in compression ratio not to be exceeded, so as not to risk the occurrence of a surge phenomenon. In a known manner, a line, called the operating line, is defined, associating the compression ratios obtained as a function of the flow rate, when the turbomachine 100 is in stabilized operation. The positioning of this operating line is left to the discretion of the designer of the turbomachine 100 and the distance from this operating line to the surge line represents the surge margin. It should be noted that the efficiency of the compressor (compression work supplied to the air, relative to the work supplied to drive it in rotation) is, as a first approximation, better as one gets closer to the surge line.Conversely, the accelerations requested by the pilot from a stabilized operation (transient phase) to obtain an increase in thrust, result at the compressor level in an excursion of the operating point which takes place in the direction of the pumping line.

[0008] Indeed, an additional injection of fuel into the combustion chamber 113 causes an almost instantaneous increase in the compression ratio, even though the rotation speed does not have time to increase due to inertia. The variation in enthalpy brought to the fluid by the combustion of the added fuel then generates an increase in the work provided by each turbine and, consequently, an increase in the rotation speed of the corresponding body. This is reflected in the compressor diagram by a return of the operating point to the operating line when the speed stabilizes again, at an operating point which corresponds to a higher flow rate than that of the previous operating point.

[0009] The designer of a 100 turbomachine must therefore try to optimize the placement of the operating line by placing it as high as possible, so as to benefit from better efficiency for its compressors, while keeping a sufficient distance from the pumping line to allow safe accelerations.

[0010] In order to avoid any surge phenomenon, a turbomachine 100 comprises a regulation system implemented by an electronic unit. With reference to the, the regulation system comprises a stabilized management module 31, a transient intention detection module 32, a speed trajectory generation module 33, a transient management module 33', a selection module 34, an integration module 35 as well as a stop management module 36.

[0011] The transient management module 33' provides a correction quantity to the selection module 34 as a function of the difference between the speed NL of the turbomachine 100 and the trajectory from the module for generating a speed trajectory 33. The stabilized management module 31 provides a correction quantity to the selection module 34 as a function of the difference between the speed NL of the turbomachine 100 and the set speed NL CONS The NL regime can correspond to different types of regime, in particular, a blower regime, a pressure setpoint known by its English acronym EPR (Engine Pressure Ratio), a high pressure setpoint or other.

[0012] The NL deposit system CONS is proportional to the position of the control lever that can be manipulated by the pilot of the aircraft. Such a stabilized management module 31 is known to those skilled in the art and will not be presented in further detail.

[0013] The purpose of the transient intention detection module 32 is to detect a transient intention desired by the pilot. The transient intention detection module 32 determines a difference between the NL speed of the turbomachine 100 and the setpoint NL speed. CONS . When the control lever remains in a constant position and the stabilized management module 31 is implemented, the actual speed NL of the turbomachine 100 is stationary and equal to the set speed NL CONS . If the pilot moves the control lever, the set speed NL CONS varies instantaneously. On the contrary, the NL regime does not vary instantaneously due to the inertia of the turbomachine 100 and the stabilized management module 31. Thus, the transient intention detection module 32 detects a transient intention when the difference between the setpoint regime NL CONS and the actual regime NL is greater than a predetermined threshold S2.

[0014] In the case of an acceleration request, if the speed difference is greater than the predetermined threshold S2 (NL CONS - NL > S2), an acceleration request is detected. Similarly, in the case of deceleration, if the speed difference is greater than the predetermined threshold S2 (NL - NL CONS > S2), a deceleration request is detected. When a transient phase is detected, the transient intention detection module 32 generates an activation signal, which is transmitted to the engine trajectory generation module 33 and the selection module 34 as illustrated in.

[0015] In the case of an acceleration request, the engine speed trajectory generation module 33 determines an engine speed setpoint for acceleration (acceleration trajectory). Similarly, in the case of deceleration, the engine speed trajectory generation module 33 determines an engine speed setpoint for deceleration (deceleration trajectory). Depending on the generated trajectory, the engine speed trajectory generation module 33 provides a correction quantity to the selection module 34.

[0016] Such a module for generating a regime trajectory 33 is known to those skilled in the art, in particular from patent application US2013 / 0008171 and patent application FR2977638A1, and will not be presented in more detail.

[0017] In this example, the selection module 34 is configured to receive an activation signal from the transient intention detection module 32. The selection module 34 selects the correction quantity from the stabilized management module 31 in the absence of reception of an activation signal and selects the correction quantity from the transient management module 33' in the event of reception of an activation signal. Such a selection module 34 is known to those skilled in the art and will not be presented in further detail. The selected correction quantity is provided to the integration module 35. The integration module 35 determines the fuel flow setpoint WFcmd by integration of the selected correction quantity.

[0018] The stop management module 36 limits the value of the fuel flow setpoint WFcmd determined by the integration module 35. In a known manner, the stop management module 36 implements a stop, called a C / P stop known to those skilled in the art in order to protect the turbomachine against surge. In this example, the stop management module 36 makes it possible to define stop setpoints in acceleration and deceleration. Such stops are known to those skilled in the art and will not be presented in more detail.

[0019] The engine speed trajectory generation module 33 and the limit stop management module 36 make it possible to define an acceleration trajectory which has the effect of restricting the fuel flow setpoint WFcmd in order to avoid surge. Such a regulation system is known from patent application FR2977638A1 and will not be presented in more detail. Incidentally, it is known to protect an engine against the surge phenomenon during transients by taking into account an acceleration setpoint during regulation (see for example US4543782 and US 2003 / 0094000).

[0020] In order to improve the response time of a turbomachine during a transient phase (acceleration, deceleration, etc.), it has been proposed to equip the turbomachine with an electric machine in order to provide additional electric torque to increase the speed of the turbomachine without leading to a surge phenomenon. To this end, patent application WO2016 / 020618 discloses a turbomachine for an aircraft comprising an electric machine for taking power from the low-pressure shaft and injecting power into the high-pressure shaft. Incidentally, patent applications FR3116865A1 and FR3087491A1 disclose methods for controlling a turbomachine comprising an electric motor.

[0021] To reduce the energy costs associated with the electric machine, it is known to use the electric machine only during a transient phase. In practice, the electric machine is stopped at the end of the transient phase and this results in a sudden loss of torque (step-type modification) which is automatically compensated by a modification of the fuel flow setpoint WFcmd.

[0022] This can cause significant variations in speed and repeated activations / deactivations of the electric machine, which can penalize the thrust as well as the lifespan of the electric machine.

[0023] The invention thus aims to eliminate at least some of these drawbacks by proposing a method for controlling a turbomachine making it possible to improve the management of the electric machine after a transient phase. PRESENTATION OF THE INVENTION

[0024] To this end, the invention is the result of technological research aimed at very significantly improving the performance of aircraft and, in this sense, contributes to reducing the environmental impact of aircraft. For this purpose, the invention relates to a method for controlling a turbomachine comprising a fan positioned upstream of a gas generator and delimiting a primary flow and a secondary flow, said gas generator being traversed by the primary flow and comprising a low pressure compressor, a high pressure compressor, a combustion chamber, a high pressure turbine and a low pressure turbine, said low pressure turbine being connected to said low pressure compressor by a low pressure rotation shaft and said high pressure turbine being connected to said high pressure compressor by a high pressure rotation shaft, the turbomachine being configured to be in a transient phase or in a stabilized phase,the turbomachine comprising an electric machine configured to apply a torque to the low pressure rotation shaft or to the high pressure rotation shaft during the transient phase, method in which a fuel flow setpoint in the combustion chamber and an electric torque setpoint supplied to the electric machine are determined, the control method comprising a first fuel control loop determining the fuel flow setpoint and a second torque control loop determining the electric torque setpoint.,

[0025] The invention is remarkable in that:The second torque control loop is configured to determine the electrical torque setpoint from a determined transient torque setpoint, a previous electrical torque setpoint and a transient phase indicator,The second torque control loop is configured, when the transient phase indicator is inactive, to determine that the electrical torque setpoint is equal to a control setpoint, the control setpoint being determined from a previous control setpoint, a time constant and the previous electrical torque setpoint according to a decreasing mathematical law of the first order.

[0026] Thanks to the invention, the electrical torque setpoint is reduced quickly and in a controlled manner while limiting the static error. This makes it possible to reduce electrical consumption after a transient phase while avoiding an abrupt reset that could lead to compensations by the first fuel control loop. The reset of the electrical torque setpoint is thus optimal.

[0027] Preferably, the mathematical law is equal to In which TRQcont is the control setpoint TRQcont-1 is the previous control setpoint tau is the time constant TRQcmd-1 is the previous electric torque setpoint t is the time.

[0028] Advantageously, the time constant tau is an image of the speed of cancellation of the electric torque and can advantageously be parameterized.

[0029] Preferably, the torque control loop is configured to reset the control setpoint when the absolute value of the previous control torque setpoint is less than a predetermined turn-off constant. This avoids a very slow shutdown of the electrical input when the electrical input is low. Any untimely use of the electrical machine is thus avoided.

[0030] In one aspect, the time constant governing the resetting of the control setpoint is configurable. This allows the torque resetting dynamics to be conveniently adjusted in line with the dynamics of the first fuel control loop.

[0031] In one aspect, the torque control loop is configured to receive transient indicators output by the fuel control loop and to determine the transient phase indicator from the transient indicators.

[0032] According to one aspect, the torque control loop is configured to add an aircraft power draw setpoint to the electrical torque setpoint. Thus, the electrical torque setpoint can take into account transient regimes but also the aircraft's electrical energy requirements.

[0033] The invention also relates to a computer program comprising instructions for executing the steps of a control method as presented above when said program is executed by a computer.

[0034] The invention also relates to an electronic control unit for a turbomachine comprising a memory including instructions of a computer program as presented previously.

[0035] The invention also relates to a turbomachine comprising an electronic unit as presented previously. PRESENTATION OF FIGURES

[0036] The invention will be better understood upon reading the following description, given by way of example, and referring to the following figures, given by way of non-limiting examples, in which identical references are given to similar objects.

[0037] This is a schematic representation of a turbomachine according to the prior art.

[0038] is a schematic representation of a system for regulating a fuel flow setpoint according to the prior art.

[0039] This is a schematic representation of a turbomachine according to one embodiment of the invention.

[0040] This is a schematic representation of a system for regulating a fuel flow setpoint and an electric torque setpoint.

[0041] This is a schematic representation of an electrical torque setpoint control loop.

[0042] This is a schematic representation of a transient determination block.

[0043] This is a schematic representation of a control module.

[0044] This is a schematic representation of several mathematical laws of torque reduction to zero.

[0045] This is a schematic representation of torque reductions to zero in decreasing first order for different time constants.

[0046] This is a schematic representation of the evolution of several physical quantities over time during changes in the turbomachine's regime.

[0047] This is a schematic representation of a system for regulating a fuel flow setpoint and a torque setpoint, taking into account an electrical draw from the aircraft in the regulation of the electrical torque setpoint.

[0048] This is a schematic representation of an electrical torque setpoint regulation loop taking into account the electrical draw from the aircraft.

[0049] It should be noted that the figures set out the invention in detail to implement the invention, said figures can of course be used to better define the invention if necessary. DETAILED DESCRIPTION OF THE INVENTION

[0050] With reference to the, there is shown schematically a turbomachine T of the double-flow and double-spool turbojet type for aircraft. In a known manner, the turbomachine T comprises, from upstream to downstream in the direction of gas flow, a fan 10, a low-pressure compressor 11, a high-pressure compressor 12, a combustion chamber 13 which receives a fuel flow setpoint WFcmd, a high-pressure turbine 14, a low-pressure turbine 15 and a primary exhaust nozzle 16. The low-pressure (or LP) compressor 11 and the low-pressure turbine 15 are connected by a low-pressure shaft 21 and together form a low-pressure body. The high-pressure (or HP) compressor 12 and the high-pressure turbine 14 are connected by a high-pressure shaft 22 and together form, with the combustion chamber 13, a high-pressure body. The blower 10, which is driven by the low pressure shaft 21, compresses the ingested air.This air is divided downstream of the fan 10 between a secondary air flow which is directed directly towards a secondary nozzle (not shown) through which it is ejected to contribute to the thrust provided by the turbomachine T, and a so-called primary flow which enters the gas generator, consisting of the low-pressure body and the high-pressure body, then which is ejected into the primary nozzle 16. In a known manner, to modify the speed of a turbomachine T, the pilot of the aircraft modifies the position of a control lever which makes it possible to modify the fuel flow setpoint WFcmd in the combustion chamber 13.

[0051] With reference to the, the turbomachine T further comprises an electric motor ME configured to provide additional torque to the low pressure shaft 21 or the high pressure shaft 22. The operation of the turbomachine T is controlled by an electronic unit 20 which obtains signals representing operating parameters of the turbomachine T, in particular a speed NL of the turbomachine T, to provide the fuel flow setpoint WFcmd and a torque setpoint TRQcmd to the electric motor ME. The speed NL may correspond to different types of speed, in particular, a fan speed, a pressure setpoint known by its English acronym EPR (Engine Pressure Ratio), a high pressure speed setpoint or other.

[0052] As illustrated in the, the electronic unit 20 comprises a regulation system comprising a first loop B1 for regulating the fuel flow setpoint WFcmd, hereinafter referred to as “first fuel loop B1”, and a second loop B2 for regulating the electric torque setpoint TRQcmd, hereinafter referred to as “second torque loop B2”.

[0053] As illustrated in the, the first fuel loop B1 comprises:A temperature input T2a turbomachine speed input NLa setpoint speed input NL CONSdefined by the position of the control lever that can be manipulated by the pilot of the aircraft, a fuel flow setpoint output WFcmd transmitted to the turbomachine T and a plurality of output indicators: an indicator of a transient acceleration request TopAccel an indicator of a transient deceleration request TopDecel an indicator of an acceleration stop TopButeeAccel defined by the saturation of the corrector control by the acceleration C / P stop an indicator of a deceleration stop TopButeeDecel defined by the saturation of the corrector control by the extinction C / P stop an engine speed trajectory setpoint for acceleration NLTrajAccCons an engine speed trajectory setpoint for deceleration NLTrajDecelCons

[0054] Still with reference to the, the second torque loop B2 receives as input all the output indicators generated by the first fuel loop B1, i.e. TopAccel, TopDecel, TopButeeAccel, TopButeeDecel, NLTrajAccCons, NLTrajDecelCons, as well as the speed input NL of the turbomachine T.

[0055] Thanks to this regulation system, the second torque loop B2 provides an adaptive torque setpoint TRQcmd based on the behavior of the first fuel loop B1, which remains the priority. In this example, the first fuel loop B1 also includes a static pressure input in the combustion chamber PS3.

[0056] In detail, with reference to the, the second torque loop B2 comprises a processing block B21 configured to determine a transient torque setpoint TRQtrans from the inputs NLTrajAccCons, NLTrajDecelCons, as well as the speed input NL of the turbomachine T. Such a processing block B21 is known from the prior art, in particular, from patent application WO2016 / 020618. The transient torque setpoint TRQtrans makes it possible to respond electrically to the needs of the turbomachine T during a transient regime.

[0057] The second torque loop B2 further comprises a control module 3, shown schematically in, configured to determine the electrical torque setpoint TRQcmd from the transient torque setpoint TRQtrans, a previous electrical torque setpoint TRQcmd-1 and a transient phase indicator TopTrans.

[0058] In this example, the transient phase indicator TopTrans is active when the turbomachine T is in transient mode. For this purpose, as illustrated in the, the second torque loop B2 comprises a transient determination block B22 to determine the transient phase indicator TopTrans. With reference to the, the transient phase indicator TopTrans is determined from the inputs TopAccel, TopDecel, TopButeeAccel, TopButeeDecel. In particular, the transient phase indicator TopTrans is active: when acceleration is requested and when the acceleration stop is already reached (TopAccel and TopButeeAccel activated) when deceleration is requested and when the deceleration stop is already reached (TopDecel and TopButeeDecel activated).

[0059] With reference to the, the control module 3 comprises a first AC switch configured to determine the electrical torque setpoint TRQcmd from the transient torque setpoint TRQtrans and a control setpoint TRQcont based on the transient phase indicator TopTrans.

[0060] Still referring to the, as long as the transient indicator TopTrans is active, the first AC switch determines that the electric torque setpoint TRQcmd is equal to the transient torque setpoint TRQtrans. Indeed, when the turbomachine T is in transient mode, the electric motor ME provides a torque meeting the transient needs of the turbomachine T.

[0061] When the TopTrans transient indicator is inactive, the first AC switch determines that the electrical torque setpoint TRQcmd is equal to the control setpoint TRQcont, which aims to reduce the electrical torque. The control setpoint TRQcont will now be presented.

[0062] The control module 3 further comprises a second switch CB configured to determine the control setpoint TRQcont from a previous electrical torque setpoint TRQcmd-1 and an intermediate control setpoint TRQcinter as a function of the transient phase indicator TopTrans.

[0063] The control module 3 further comprises a third DC switch configured to determine the intermediate control setpoint TRQcinter from a reset setpoint and a reduced control setpoint TRQcontr based on a comparison indicator Icomp. The reduced control setpoint TRQcontr is determined from a previous electrical torque setpoint TRQcmd-1 and a previous control setpoint TRQcont-1.

[0064] In this example, the previous electric torque setpoint TRQcmd-1 and the previous control setpoint TRQcont-1 are respectively determined by integrators int1, int2.

[0065] The different parameters will now be presented.

[0066] In this example, the reduced control setpoint TRQcontr is determined in a reduction loop 31 from the previous control setpoint TRQcont-1, a time constant tau and the previous electric torque setpoint TRQcmd-1.

[0067] As long as the turbomachine T is in transient mode, the second switch CB determines that the control setpoint TRQcont is equal to the previous electrical torque setpoint TRQcmd-1. This control setpoint TRQcont is used by the reduction loop 31 to determine the reduced control setpoint TRQcontr. This advantageously makes it possible to synchronize the reduction loop 31 with the electrical torque setpoint TRQcmd so that the value of the previous control setpoint TRQcont-1 is in continuity with the values ​​of the electrical torque setpoint TRQcmd. When the turbomachine T returns to steady state, the second switch CB determines the control setpoint TRQcont as the intermediate torque setpoint, the electrical torque at the starting point of the reset is thus the electrical torque at the arrival point of the transient mode. The transition is advantageously made smoothly.

[0068] As shown in, the previous control setpoint TRQcont-1 and a target value 0 (reset setpoint) are compared by an adder add1 to determine a primary deviation eps1. The primary deviation eps1 is then multiplied by the time constant tau in a multiplier block to obtain a secondary deviation eps2. The secondary deviation eps2 is then added to the previous electrical torque setpoint TRQcmd-1 via an adder add2 to determine the reduced control setpoint TRQcontr.

[0069] In other words, the reduction loop 31 makes it possible to determine the control setpoint TRQcont according to the following decreasing first-order mathematical law.

[0070]

[0071] The absolute value of the primary deviation eps1 is determined by an absolute value block abs, and is compared with a predetermined extinction constant e by a comparison block comp to determine a comparison indicator Icomp. In practice, the comparison indicator Icomp is active if the absolute value of the primary deviation eps1 is less than the predetermined extinction constant e. The predetermined extinction constant e is configured to be close to 0 (reset setpoint) in order to force a reset of the electrical torque when the electrical requirements are low. This prevents unwanted use of the electrical machine ME. It also prevents slow convergence to zero with a first-order mathematical law.

[0072] In this example, still with reference to the, when the control indicator Icomp is inactive, the third switch CC determines that the intermediate control setpoint TRQcinter is equal to the reduced control setpoint TRQcontr. This implementation advantageously makes it possible to reduce the output value of the switch CB according to the mathematical law of decreasing first order as long as the control indicator Icomp is inactive. The turbomachine T can thus move from one stabilized regime to another while preserving electrical resources.

[0073] Thanks to the invention, with reference to the, during a transition from a transient regime phase Rtrans to a stabilized regime phase Rstab, the control setpoint TRQcont is reset progressively according to a first-order mathematical law RAZ2 which makes it possible: To limit the jolts on the electrical machine ME compared to a sudden reset according to a mathematical law defining a step RAZ0 and To preserve the electrical resources compared to a very progressive reset according to a mathematical law defining a decreasing ramp RAZ1.

[0074] A sudden reset by step RAZ0 also has the disadvantage of causing transition problems between the transient regime phase Rtrans and the stabilized regime phase Rstab and untimely switches between these two regimes. A very gradual reset according to a decreasing ramp RAZ1 also has the disadvantage of causing a continuous error on the electrical torque.

[0075] Preferably, the time constant tau of the first-order mathematical law of the reduction loop 31 is configurable. With reference to the representing several values ​​of time constant tau1, tau2, tau3, the speed of the response can thus be adjusted.

[0076] An example of implementation will be presented with reference to the increase in speed decided by the pilot of the aircraft.

[0077] As illustrated in curve C1, during a request for an increase in speed, the low pressure speed setpoint NLcons increases sharply at a first instant t1 which starts a transient speed phase Rtrans. The low pressure speed NL gradually follows the low pressure speed setpoint NLcons in order to avoid any surge phenomenon of the turbomachine T. At a second instant t2, the low pressure speed NL is close to the low pressure speed setpoint NLcons, which ends the transient speed phase Rtrans. The transient speed phase Rtrans is preceded by a first phase of stabilized speed Rstab1 and followed by a second phase of stabilized speed Rstab2

[0078] As illustrated in curve C2, the high pressure torque setpoint NHcons is reactively followed by the synergistic cooperation between the fuel setpoint WFcmd (Curve C3) and the electric torque setpoint TRQcmd (Curve C4).

[0079] As illustrated in curve C3, the fuel setpoint WFcmd increases progressively during a transient regime phase Rtrans.

[0080] During the transient phase Rtrans, as illustrated in curve C4, the transient indicator TopTrans is active and the electrical torque setpoint TRQcmd corresponds to the transient torque setpoint TRQtrans. The reduction loop 31 is disconnected from the output of the second torque loop B2. In this example, the second control loop B2 gradually increases the torque of the electric machine on the high-pressure shaft 22. This results in a gradual increase in the rotational speed of the high-pressure shaft 22.

[0081] After the end of the transient phase Rtrans, the transient indicator TopTrans is inactive (the acceleration transient indicator TopAccel is lowered) and the torque setpoint TRQcmd is gradually reset to zero according to the first-order mathematical law. This allows the first fuel loop B1, which has regained control over the fuel setpoint WFcmd, to regulate the rotational speed of the low-pressure shaft 21 without disturbance. When the primary deviation eps1 is small compared to the predetermined extinction constant e, the electrical torque setpoint TRQcmd is reset directly to zero to preserve electrical resources

[0082] According to one aspect of the invention, with reference to the, the second torque loop B2 also receives as input an aircraft sampling instruction TRQaero to meet the electrical needs of the aircraft, in particular, to enable electrical generation.

[0083] For this purpose, as illustrated in the, the second torque loop B2 further comprises an adder 4 which adds an aircraft sampling setpoint TRQaero to the electrical torque setpoint TRQcmd determined by the control module 3. Thus, advantageously, only the part of the electrical torque setpoint TRQcmd linked to the transient regime is reset to zero. The electrical machine ME can continue to supply electrical energy to the aircraft.

Claims

Method for controlling a turbomachine (T) comprising a fan (10) positioned upstream of a gas generator and delimiting a primary flow and a secondary flow, said gas generator being traversed by the primary flow and comprising a low pressure compressor (11), a high pressure compressor (12), a combustion chamber (13), a high pressure turbine (14) and a low pressure turbine (15), said low pressure turbine (15) being connected to said low pressure compressor (11) by a low pressure rotation shaft (21) and said high pressure turbine (14) being connected to said high pressure compressor (12) by a high pressure rotation shaft (22), the turbomachine (T) being configured to be in a transient phase or in a stabilized phase,the turbomachine comprising an electric machine (ME) configured to apply a torque to the low-pressure rotation shaft (21) or to the high-pressure rotation shaft (22) during the transient phase, in which method a fuel flow setpoint (WFcmd) in the combustion chamber (13) and an electric torque setpoint (TRQcmd) supplied to the electric machine (ME) are determined, the control method comprising a first fuel control loop (B1) determining the fuel flow setpoint (WFcmd) and a second torque control loop (B2) determining the electric torque setpoint (TRQcmd), the second torque control loop (B2) being configured to determine the electric torque setpoint (TRQcmd) from a determined transient torque setpoint (TRQtrans), a previous electric torque setpoint (TRQcmd-1) and a transient phase indicator (TopTrans),the second torque control loop (B2) being configured, when the transient phase indicator (TopTrans) is inactive, to determine that the electrical torque setpoint (TRQcmd) is equal to a control setpoint (TRQcont), the control setpoint (TRQcont) being determined from a previous control setpoint (TRQcont-1), a time constant (tau) and the previous electrical torque setpoint (TRQcmd-1) according to a decreasing mathematical law of the first order., Method for controlling a turbomachine (T) according to claim 1, in which the mathematical law is equal to In which TRQcont is the control setpoint TRQcont-1 is the previous control setpoint tau is the time constant TRQcmd-1 is the previous electric torque setpoint t is the time. Method for controlling a turbomachine (T) according to one of claims 1 to 2, in which the torque control loop (B2) is configured to reset the control setpoint (TRQcont) to zero when the absolute value of the previous control torque setpoint (TRQcont-1) is less than a predetermined extinction constant (e). Method for controlling a turbomachine (T) according to one of claims 1 to 3, in which the time constant (tau) governing the resetting of the control setpoint (TRQcont) is configurable. Method for controlling a turbomachine (T) according to one of claims 1 to 4, in which the torque control loop (B2) is configured to receive transient indicators (TopAccel, TopButeeAccel, TopDecel, TopButeeDecel) emitted by the fuel control loop (B1) and to determine the transient phase indicator (TopTrans) from the transient indicators (TopAccel, TopButeeAccel, TopDecel, TopButeeDecel). Method for controlling a turbomachine (T) according to one of claims 1 to 5, in which the torque control loop (B2) is configured to add an aircraft power extraction setpoint (TRQaéro) to the electric torque setpoint (TRQcmd). Computer program comprising instructions for executing the steps of a control method according to one of claims 1 to 6 when said program is executed by a computer. Electronic control unit (20) for a turbomachine (T) comprising a memory including instructions of a computer program according to claim 7. Turbomachine (T) comprising an electronic unit (20) according to claim 8.

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